In photography, a conventional camera flash (visible or non-visible spectrum) is used to improve image picture quality in low light situations, by illuminating the scene with a burst (single pulse or multiple pulses) while a picture is taken. Typical flash light source may include a Light Emitting Diode (LED) or may include gas discharge lamps or even may even include a LASER. Typical camera includes a CCD, CMOS or a hybrid sensor with single exposure duration per a sensor single frame read-out.
Prior art such as U.S. Pat. No. 7,962,031 B2, entitled “Pulsed control of camera flash” is directed to improve the ability to subsequently discriminate the high frequency or edge components of the picture, during the subsequent deblurring or motion compensation operation. The described technique does not provide any means for illuminating a selected volume of the captured scenery image.
Another prior art such as U.S. Pat. No. 8,194,126 B2, entitled “Gated imaging” is directed towards a gated camera imaging system and method, utilizing a laser device for generating a beam of long duration laser pulses toward a target. A camera receives the energy of the pulses reflected from the target. The camera gating is synchronized to be set ‘OFF’ for at least the duration of time it takes the laser device to produce a laser pulse in its substantial entirety, including an end of the laser pulse, in addition to the time it takes the laser pulse to complete traversing a zone proximate to the system and back to the camera. The camera gating is then set ON for an ON time duration thereafter, until the laser pulse reflects back from the target and is received in the camera. The laser pulse width substantially corresponds to at least the ON time duration.
Israeli patent application IL170098 discloses a gated camera imaging system and method, utilizing a laser device for generating a beam of long duration laser pulses toward a target. A camera receives the energy of light reflexes of the pulses reflected from the target. The camera gating is synchronized to be set OFF for at least the duration of time it takes the laser device to produce a laser pulse in its substantial entirety, including an end of the laser pulse, in addition to the time it takes the laser pulse to complete traversing a zone proximate to the system and back to the camera, and set ON for an ON time duration thereafter until the laser pulse reflects back from the target and is received in the camera. The laser pulse width substantially corresponds to at least the ON time duration. Preferably, the laser device includes a Diode Laser Array (DLA).
Israeli patent application IL177078 discloses an imaging system, including a transmission source providing pulse(s), and a gated sensor for receiving pulse reflections from objects located beyond a minimal range. The pulse and the gate timing are controlled for creating sensitivity as a function of range, such that the amount of the energy received progressively increases with the range. Also an imaging method, including emitting pulse(s) to a target area, receiving reflections of pulses reflected from objects located beyond a minimal range, the receiving includes gating detection of the reflections, and progressively increasing the received energy of the reflections, by controlling the pulses and the timing of the gating.
Prior art does not provide a selective and controllable scene volume imaging in low light level conditions nor does it address imaging enhancement in low-light level in harsh weather such as rain or snow versus the proposed method. In addition prior art does not provide any solution to provide a unified image enhancement in a certain range in low-light level conditions.